1. Field of the Invention
The present invention relates to an apparatus and method of encoding and decoding color images in an electronic device.
2. Description of the Related Art
Digital image data includes Red (R), Green (G), and Blue (B) color components or luminance (Y) and a plurality of color difference components (chrominance (C)). Color difference components may be produced from differences between the luminance signal (Y) representing the brightness of a video on an electronic device and the three basic colors signals, in which case the differences may be three color difference components: (RY), (GY) and (BY). The three basic colors may be reproduced by using the two color difference components, (RY) and (BY).
A digital image may be formed with a ratio of the luminance Y and the color difference components (B−Y and R−Y), 4:n:n, where the number, ‘4’ denotes a sampling rate of a standard frequency 13.5 MHz, for converting analog TV signals into digital signals, and ‘n’ and ‘m’ denote the respective color difference components. There may be sampling schemes considering ratios of luminance and color difference components, e.g., 4:4:4, 4:2:2, and 4:1:1. The 4:4:4 scheme indicates that three components channels are sampled at 13.5 MHz. The 4:2:2 scheme indicates that when the Y signal is sampled every line at 13.5 MHz, the color difference signals are sampled every two lines at 6.75 MHz. The 4:1:1 scheme indicates that when the Y signal is sampled every line at 13.5 MHz, the color difference signals are sampled every four lines at 3.37 MHz.
Conventional electronic devices reduce the rates of color difference components to be less than the rate of a luminance component in a digital image including, for example, a luminance component, first color difference component and second color difference component. As such, the number of color difference components is reduced compared to the rate of the luminance component. In that case, although the size of image data may be reduced, the capability of displaying images also decreases. Accordingly, there is a need in the art for an improved method and apparatus for encoding and decoding images in an electronic device, such that the integrity of an image display is maintained.